Disgust is an universal emotion, but unlike emotions like fear and anger, disgust must be learned. This is the main conclusion of Dr. Rachel Herz's latest book, That's Disgusting: Unraveling the Mysteries of Repulsion. In a recent interview (BSP 86), Dr. Herz told me why she spent the last several years studying this rather unusual subject. We also discussed what the study of disgust can tell us about how our brains process emotion.